In fact it specifically mentions anonymous communications in a variety of forms.

Either (a) communicates with a person, anonymously or otherwise, by telephone, or by telegraph, mail or any other form of written communication, in a manner likely to cause annoyance or alarm; or (b) causes a communication to be initiated by mechanical or electronic means or otherwise with a person, anonymously or otherwise, by telephone, or by telegraph, mail or any other form of written communication, in a manner likely to cause annoyance or alarm; or Makes a telephone call, whether or not a conversation ensues, with no purpose of legitimate communication;...

I can only recommend a more in-depth reading for you. At the very least you owe it to yourself to have basic knowledge of the laws in question before you go about declaring what’s legal and illegal.